SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: ghett0man on June 27, 2016, 02:48:48 PM
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Ford 460 stock internals (except the cam) with a holly DP 750.
Went to fire the boat up before the trip and gas shot up out of primary vent tube. So I checked the floats and all was good as well as the needle and seats. Cranked it again and another geyser of fuel blew thru the vent tube. So I switch the primary and secondary needle/seats and the same thing happened again.
Check the holly website and they said anything over 7 psi will cause a flooding situation. I was at 8 when cranking. So I got another fuel pump rated for 6.5 psi and all was good.
Went out for some bug runs and at 4K RPMs I would lose all pressure, but if I stayed under 4K rpm all was good. Ran into Parker and got some needle/seats and put the old 8 psi pump on and all was normal.
My question is how is everyone else configuring their fuel delivery? Are my needle/seats gonna go bad every year? Should I just keep some on hand? Or should I get a 8+ psi fuel pump and regulate it down?
I've search here on the boards and didn't come across a thread with the same issue as mine. I know the different options out there with self regulating fuel pumps, but I'm fine with a mechanical, or do I need a higher volume pump with a lower PSI?
I'm just a little confused with holly saying 7 psi is bad, but my I need something rated at 8 psi to run over 4K.
Thoughts?
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Last night....I was drunk for a week.
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It Sounds like u have a volume issue not a pressure issue. How many gph is is your pump and how big are your fuel lines?
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I think the pump giving u 6psi doesn't pump enough fuel once you get into the high rpms. And most carb guys have told me to run between 5.5-6.5 and anything over 7 you'll start having flooding issues
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Running 3/8" lines from the tanks to the pump and 3/8" lines from pump to carb with a fuel filter in between. I was suspecting the volume was to low but I'm not sure how to calculate the volume needed to run.
Is the higher pressure blowing the o rings out on my needle/seats? They hold for a year or so and then can't handle the pressure?
Thanks for the responses so far.
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Last night....I was drunk for a week.
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where is your pump mounted/what kind of pickups are you using?
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I think u just need to right pump. I love my electric pump with a regulator. Only other thing I'd check is the fuel lines or filter being clogged. Other than that I'd say just a shitty pump
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I have a brand new Holley regulator of you need it
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The pump is mounted in the normal mechanical pump Spot off the side.
I put my old pump back on with new needle and seats and all is good.
So the needle and seats were bad but I replaced them a year ago.
So I was wonder if this is a common problem. The 8psi pump blowing the seals every year or is something else going on. The boat was in the garage all year and wasn't outside.
I have options, but I'm just trying to figure out the best configuration based off of others experience. I don't wanna just buy parts to try and figure it out if others have had this issue.
So maybe a 5.5-6.5 psi pump with more volume than a stock 460 fuel pump?
Or a higher PSI pump regulated down to whatever my sweet spot would be?
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Last night....I was drunk for a week.
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I have a brand new Holley regulator of you need it
I might take you up on that Steve. I'll PM you later. Thanks
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Last night....I was drunk for a week.
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I know if I were to go to a mechanical pump I would have one built by clay smith.
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I run a Holley mechanical pump with -10 fuel lines regulated at 6.5 psi. The motor is 850 hp. It will work fine you just need the volume and a regulator.
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I run the Holley 130 gph mechanical pump regulated down to 6.5psi on a mild 450hp 460. Works great.
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Thnks for the info guys. I think I know which way to go.
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Last night....I was drunk for a week.